Vacuum servo brake



Feb. z3, 1932. H. H. ALBINSQN 1,846,017

VACUUM SERVO BRAKE Filed Aug. 19, 1929 Patented Feb. 23, 1932 HAROLD LEI. ALBINSON, I' DETROIT, IICHIGAN, ASSIGNOB'TO GENERAL iroerons RESEARCH COBPORATIGN,. 0F DETROIT, MICHIGAN, .A CORPORATION 0F DELL- WARE vacuum snavo anun Application led August 19, 1929. Serial Inl-386,922.

This invention relates tobrakes and particularly to an improvement in the mechanism for controlling the brakes of vehicles by huid pressure.

An objectief the invention is to provide operating means for vehicle s ling the action`of engine suction which 1s used to supplement the manually applied forces. Another object is to mount both the I edal and the brake lever on the same pivot -ulcrum and to provide means connecting the arms of said pedal and lever whereby the supplementary applied force is controlled.

Other objects and advantages will be understood from the following description.

ln the drawings, Figure l is a view in sidey elevation, partly in section. Figure 2 is a view in end elevation. Figure 3 is a vertical section through the control valve. Figure 4 is a view taken as indicated by the line 4-4 of Figure l.

Reierring by reference characters to the drawings, numeral 5 re resents a part of the floor board of the bodly, this being represented merely to show the relation of the operatin parts of the device to the vehicle. At 7 is sliown a shaft mounted in any convenient way benea h the floor board. Lever 9 is rotatable about shaft 7 and is the manually operated element of the brake mechanism. It may be handoperated or, as shown in the drawings, it may be a pedal extending through the Hoor board. It has a downwardly directed arm, 11. A second lever, 13, which may be called a brake lever, since it has one arm, 15, connected by a link, 17, to any preierred kind of brake hook-up, is formed at the base of arm, 15, with a pair of s aced arms, 19, apertured to pivot on shaft, one pivotal connection belng on each side of the pedal pivot. The extreme ends of arm, 19, are apertured to carry. pivot pin, 21, on which rotates a lever, 23, lying generally in parallelism with arms, 19. a re-action lever. This lever, 23, has a forked end, 25, between the arms, 19. The forked end, 25, is pivotcd by a pin, 27, to the end of arm V11. Arms 19 are formed with elongated slots, 28, through which pin 27 passes and which slots limit the movement of pin .1s held against the flat face o brakes control-l which avoids friction Lever 23 may be called 19, has a pin, 29

27. One

This pin is locati-.

of the arms,

pro- ]ectmg therefrom.

Just

above pin 27. Onthe extended end of pin 27 is pivoteda valve lever, 31. It lever 19 by a sprlng, 33, 'engaging theface of the lever and an abutment, 35, carried by pin 27. Lever 31 has a terminal slot, 37, engaging about pin 29. ts lower end is slotted as at 39 to slidingly engage a pin, 41, carried by a yoke on the end of the valve stem, 54. The lower end of lever 23 is connected by a rod, 43, to a plunger, 42, in a power cylinder or chamber, 44. The pressure conditions of the power cylinder are controlled by a valve, 46, the power c linder being operated by suction, the valve operating p ing in aconduit between any preferred source of suction and the power cylinder, 44. The power cylinder is preferably of that t pe by use of the diaphragm, and one wherein a long stroke is provided in proportion to its diameter by the. use of a tapered sleeve type of diaphragm.

his unit comprises two cup shaped halves, 45 and 47, having mating flanges, 49, fastenlng means, 51, securing the flanges together and also securing between the flanges the larger diameter end of the tapered sleeve. diaphragm, 48.' The plunger, 42, is in the form of a disc. It is of smaller diameter than the ends of the cylinder and to it is secured the smaller end of the tapered sleeve diaphragm. The rod, 43, extends through a guidin lsleeve portion, 57, of cylinder element, 4 The cylinder element, 47, may also be provided with an opening for air as shown at 50. The rod, 43, is connected to the lower' end of the re-action lever, 23, as explained above. The cvlinder element, 45, may have a member, 52, provided with an eye secured thereto for the attachment of the power unit to any convenient part of the vehicle chassis. On one side of rod 43 is carried the valve member, 46. The valve stem, 54, reciproca-tes through a guiding sleeve, 61. It carries a flange, 63, to at times engage and move a cylindricalV valve, 60, and lift it olf its seat 65. When so lifted, the suction of the manifold communicates by a pipe, not shown, with an opening, 6T, in the valve body, through the space, 69,

opened by suction valve 60 and then by openwhich the suction valve closes as the brake v ings 72 into the hollow rod 43, and to the lever swings to apply the brake and the pin interior of the power cylinder. A second 27 is again engaged by the right side of the valve, 71, slides on the valve stem, 54, and is brake lever slot. Should the suction brake 5 to be engaged and lifted oil its seat, 73, by fall to operate, there is, of course, no feel of nuts, 75, on the end of the stem. When the power brake action transmitted to the opervalve, 71, is oi its seat, the outer air is in comator and the pin 27 after engaging the left munication with the power cylinder through end of brake lever slot limits the relative the open end, 79, (covered by a dust guard, movement between the pedal and the brake 1e- 81), the open valve, 71, and the second openver and the pedal pressure operates solely uning, 72, to the hollow rod in the power cylassisted in applying the brake. If the operinder. It will be observed from Figure 2 ator fully releases the pedal, the spring72 that the connection of rod 43 with lever 23 returns the parts to their initialposition, as may be made at any one of the plurality of shown in Figure 1 and in so doing the movespaced positions. The slot on theend of lement of lever 31 opens the air valve, 1,

` ver 31 is arranged to accommodate thev selecwhereby atmospheric pressure fills the p owtion of one of these pivotal connections. The er chamber. While the suction power unit is operation of the device takes place as fol- Opratng thebrke, it Will be understood lows: that the operator, through additional pres- Figures 1 and 2 show the parts in their relsure on the pedal, may supplement the same ative position when the brakes are released, and increase the intensity of braking action. When the pedal is depressed, assuming that The arrangement described above is of partheresistance offered by the brakes is greatticular use in the installation where it is not er than that offered by the spring, 72', the convenient to associate the valve. operating pedal rotates clockwise relative to the brake mechanism with the upper arm of the brake lever, 15, which remains stationary, Since pedal in which position it may interfere with lever 15 is not moved, ivot point 21 is fixed other mechanism of the vehicle chassis. In and the moving pedal By its eonneotion with almost any case it is possible to arrange the re-action lever 23, through the instrumenlevers 23 and 31 in the relation shown and de- 30 tality of pin swings the lever, 23, in e scribed. Not only is this arrangement gencounterclookwise direction, The moving erally useful, but it permitsfboth the pedal pin, 27 swings lever 31 clockwise about its and the brake lever to be rotatably supportpivot cnter 29. It will be seen that the valve ed on one and the s ame shaft. The valve is stem 54 isthereby moved inwardly. This innot a part of-'the invention. by itself. The

'e 35 ward movement first permits the spring, 76, novel operating means mechanism is shown 5 e pin 27 carri obviousl t0 Close the air valve, 71, and then by the enas used with a simple, non-reaction valve, the agement of the ilange, 63, with valve 60, the feel being transmitted by the leverage arsuction valve will open. This reduces the rangements. The invention is also shown aspressure within the power chamber and persociated with a power cylinder wherein the 40 mits the air at the right of the lungerwia, piston or plunger is connected t0 the chemtgtpusl the plunger to the left and) with it the bei' wall b a' tapered flexible sleeve, preferclodkwise. Thisclockwise movementis eieeresult that friction, such as occurs in the 43 thereupon pulls lever 23 ably of ru ber or rubberized fabric, with the' tive through pin 27 to exert a tendency to ropiston type of cy inder, is avoided. .The

45 tate pedal 9 in acounter-clockwise direction character of the diaphragm also permits a against the footof the operator. B lthis long stroke with a minimum size of power means the operator is made aware of t e acchamber. With a. diaphragm 0f the 1.11010 tion of the ower brake mechanism. If the common, fiat type, its deflection wouldv reo rator ho ds the dal in its fixed position quire a very large chamber to get the neces- .l

by the end of the pedal Asary changes iii-volume. y remains fixed. The pull of rod 43' I claim: c Y causes lever 23 to swing about fixed pin 27 1.v In the brake operating mechanism, a

and throughi its connec 'on with the brake manuall operable lever, a concentricallyV lever, 15, (this connection'being made by pin pivoted rake lever, a rc-action lever pivo A v '21) the .brake leveris swungin aclockwise dito said brake lever, said manually operable rection to a ply the brake through the link, lever having an arm pivoted to one arm o f 17. In so omg, pin 29, moving with lever said re-action lever, the pivot pin of saidarms 15, swings lever 31 about pin 27 as a pivot. having a limited movement relative to said ThlS swinging of lever 31 is accompanied by` brake lever, a power chamber, a lunger o a closing ofthe suction valve. The brake retherein, having a. rod, a connection tween mains applied while the operator-holds the said rod and the second arm of said re-action pedal depressed. A further pressure onthe lever, a valve controlling said power 'chamal repeats the above steps, the pin 27 movber and means moved b a relative movement in the slot of the. brake lever, the suction of said brake lever 'an said pivot pin to acl .75 device operating to -apply'the brake after tutte said valve.

lll

2.. Yl'he invention denedV by claim 1 said valve member carried by the rod of said plunger.

3. ln a brake operating mechanism, nelly operable lever, hrolre lever lEorlrs pivoted on said shaft one on each side ci seid manually operable lever, a ree-action lever nfaermediatel pivoted to one end of seid lorake lever, a reke operating link connested lo the other end of said brake lever, a. pivot pin connecting the adjacent arms of the manually operated lever and the re-action lever, scid forked arms having `aligned elongered slots receiving the ends of said pivot pin, e power cylinder, a plunger therein, a plunger rod, seid rod connected to an arm of seid reaction lever, a valve member having a. seem, o. valve operating lever pivoted to said lor-olie lever, and apertured to receive said pivoted pin, seid stem connected to an arm of seid valve operating lever.

l. ln combination, a manually operable lever, n` pivoted hralre lever, said levers having erms extending in substantially parallel rele.- lson, e power unit, a control valve therefor, means pivoted lo e lirst one of said lever arms, mechanism carried by the second of said lever arms and adopted, in response no a. relative movement between said levers, to rock said pivoted means, a connection between said a mana pivot shaft therefor, a

pivotcd means and said valve whereby seid ppivoted means shell operate said valve to render said power unit active, and a connec- 'l-ion between said power unit and said brake levensaid lasenamed connection including n lever pivotally connected with both lever arms.

l testimony whereof I aix my signature.

HAROLD H. ALBINSON.

having a forked portion, the 

